The invention concerns a roll neck seal for roll bearings, where the roll neck seal has:                an annular seal body, which is nonrotatably connected with a roll neck with its bearing surface oriented coaxially with the roll axis and with at least two spaced webs that face away from the axis of the roll and that are in direct or indirect contact with an annular projection of the roll bearing, and        a reinforcing element for reinforcing the seal body.        
Neck seals of this type are preferably used for sealing roll neck bearings in rolling mills. They are intended to prevent oil from escaping from the bearing and to prevent foreign materials, for example, coolant or mill scale, from penetrating the bearing. The high speeds of rotation of the rolls of a mill train cause correspondingly high loads on the bearings and the sealing devices due to the effects of centrifugal force. To counteract the effects of the centrifugal force, the seal bodies are reinforced with a reinforcing element. The reinforcing element is incorporated in the seal body or is arranged externally between the spaced webs. FIGS. 1a to 1f show various known embodiments of neck seals.
EP 1 625 897 B1 discloses a seal for the tapered section of a roll neck of a rolling stand. The seal comprises a flexible circular seal body with a central axis and at least one flange that extends radially outward, which flange is connected by a connecting bridge to an angularly extending lip, which has converging first and second sides. The connecting bridge has a reduced thickness compared to the thickness of the flange and the lip. The converging first and second sides of the lip lead to an enlarged rim, and the lip has first and second outer surfaces, which converge to an outer edge, which lies in a reference plane parallel to the central axis A.
DE 36 01 238 C2 discloses a sealing device for roll bearings, in which the roll neck has a tapered section between the end face of the roll and the journal. A flexible annular seal body, which has a radially extending annular sealing rib on the side of the ring that faces the end face of the roll, can be pushed onto this tapered section. When the seal body is being pushed onto the tapered section of the roll neck, the radial pressure that acts to apply a bending moment stresses the annular sealing lip into a position inclined to the axial direction and resting on the outer surface of the tapered section of the roll neck. On its inner annular surface facing the outer surface of the tapered section of the roll neck, displaced parallel relative to the annular sealing lip, the seal body has circular shoulder projections, which apply a bending moment to the seal body under the axial pressure, and this bending moment counteracts the bending moment applied to the annular sealing lip.
Roll neck seals that have two webs constructed with sealing lips and a reinforcing element that supports the seal body are disclosed by DE 37 21 265 A1, EP 1 430 962 A1, EP 1 442 804 B1, EP 1 447 149 A2, WO 2005/037 455 A1, and U.S. Pat. No. 4,099,731.
The previously known sealing devices have been found to have the following disadvantages:                The externally placed steel rim (=reinforcing element) must have clearance on both sides from the webs, which support the sealing lips.        As a result of the tapered design of the roll neck, the sealing body must be variably stressed when it is pushed on and during the subsequent operation due to the unequal centrifugal forces produced by unequal arrangement of mass in the axial direction.        During placement on the roll neck, the rim slips on one side, so that the webs are inclined as a result. Therefore, the seal does not exhibit reproducible behavior.        The oil centrifugal lip on the oil-side sealing lip can bend over so far that contact occurs with the contact diameter of the oil-side sealing lip.        The rim, which is held by point welding or butt welding, can tear open at the weld. As a result, the thin steel band then acts as a knife and cuts the rubber seal during the rotation of the roll (total failure).        Due to the trend in new rolling mills to regrind the backup rolls when wear develops in the chocks, regular inspection of the neck seals is possible only when the chocks are taken down from the roll necks. However, it is just this which one wishes to avoid. As a result, the neck seals must run reliably for longer periods of time.        The rim slips in the prior art. The neck sleeve presses on the rubber, the rubber swells out; the lip no longer fits well.        Problem associated with the seal: service life, aging due to thermal stress (frictional heat), becomes hard and cracked.        